0173 Baseline Actigraphic Sleep Measures Predict Cardiovascular Responses to Sleep Deprivation and Psychological Stress

Abstract Introduction We determined whether baseline sleep measures the night before total sleep deprivation (TSD) predicted cardiovascular (CV) responses to TSD and to TSD and psychological stress. Methods We conducted a five-day experiment under controlled conditions in thirty-two healthy adults (ages 27-53; 14 females). During this experiment, CV measures were collected via echocardiography or blood pressure monitor at four assessment time points: 1) after two baseline 8h time in bed (TIB) nights (B1, B2); 2) in the morning of TSD (TSD AM; after 25h of TSD); 3) in the evening of TSD following a modified Trier Social Stress Test, which induced psychological stress (TSD PM; after 34h of TSD); and 4) after two recovery nights of 8-10h TIB. Seated stroke volume (SV), heart rate (HR), cardiac index (CI), left ventricular ejection time (LVET), systemic vascular resistance index (SVRI), mean arterial pressure (MAP), and systolic and diastolic blood pressure (SBP and DBP) were collected. Wrist actigraphy (Actiwatch Spectrum) assessed sleep indices during the second baseline night (B2) including sleep duration, sleep onset latency (SOL), wake after sleep onset (WASO), sleep efficiency (SE), percent sleep, and the timing of sleep onset, offset, and midpoint. Pearson’s correlations assessed relationships between B2 sleep metrics and TSD AM and TSD PM CV responses (p≤0.05 was significant). Results Higher WASO during baseline was significantly associated with lower SV (r=−0.374; r2=0.140) and higher SVRI (r=0.358; r2=0.128) during the TSD evening. By contrast, there were inverse relationships for percent sleep and SE during baseline, whereby these metrics were significantly associated with higher SV and lower SVRI during the TSD evening (r:−0.398-0.387; r2:0.126-0.159). In addition, a later sleep offset during baseline was significantly associated with higher MAP, SBP, and DBP during the morning and the evening of TSD (r:0.391-0.453; r2:0.153-0.205). Conclusion Our novel results found that actigraphic sleep metrics the night before TSD predicted CV responses in healthy adults, particularly during TSD and psychological stress in the evening. Thus, WASO, percent sleep, SE, and sleep offset timing during fully rested conditions are possible predictors and biomarkers for assessing the adverse cardiovascular responses to TSD and psychological stress. Support (if any) NASA grants NNX14AN49G and 80NSSC20K0243 (NG)